Conventional guns and projectile launching weapons utilize the burning of chemical propellants to achieve high projectile velocities. In recent years there has been a renewed interest in projectile launchers which utilize electromagnetic energy. Generally speaking, electromagnetic launchers promise higher projectile velocities than launchers utilizing chemical propellants. Furthermore, electromagnetic launchers reduce logistic problems because the storing and transportation of propellant materials is not required. In addition, electromagnetic launchers have potentially greater fire power and increased system survivability (reduced probability of explosion).
One prior art design currently receiving considerable attention is the electromagnetic railgun. A conventional prior art electromagnetic railgun utilizes two long parallel rails capable of carrying large current. A sliding, conducting armature is positioned between the two rails. The armature is adapted to slide between the two rails along their entire length. Application of a voltage across two ends of the two rails causes a large current pulse to flow through one rail, thence through the armature, and into the other rail. The current generates a magnetic field. The Lorentz force created by the interaction of the magnetic field with the current in the armature causes the armature to be propelled between the two rails in a direction away from the points of application of the voltage. The armature itself may be projected like a bullet at a target, or the armature may be used to push a bullet-type projectile at high velocity towards a chosen target, and the armature ultimately slowed and retained with the device for future shots. A discussion of conventional prior art electromagnetic railguns is contained in applicant's copending application, titled "Electromagnetic Injector/Railgun," Ser. No. 910,915, Filed Sept. 22, 1986, the entire disclosure which is hereby incorporated by reference.
It is obviously desirable for a railgun to be capable of rapid-fire operation. A known prior art device utilizes a high-power rapid fire switch between the railgun and the power source. The switch makes it possible to fire many shots within a short period of time. The switch has two parallel conductive circular disks with a rotating arm sandwiched between them. Each disk has a gap in its periphery. The arm makes simultaneous electrical contact with both disks. Application of a voltage across the two circular disks generates a Lorentz force which causes the arm to rotate between the disks. The periphery of each disk is also connected to one of two rails of a conventional railgun. As the self-propelled arm passes the connection between the disks and the railgun, current is delivered to the railgun and the projectile is launched between the rails of the railgun. Thus, the railgun fires each time the arm passes the connection point between the disks and the railgun. The firing rate of the railgun is governed by the speed of the rotating arm.
Another rotary switch suitable for providing railgun power is disclosed in U.S. Pat. No. 4,433,607, entitled "Switch For Very Large D.C. Currents" issued to Kemeny.
Those concerned with the development of high power rapid fire projectile launchers have long recognized the need for compact, lightweight components.
Known prior art high-power rapid fire switches can deliver approximately 1.5 megAmperes of current and weigh approximately one thousand pounds and are 36 inches in diameter. The switch must be coupled to the railgun itself and the combination is bulky, massive, and complex.